The momentary metal push button switch is made of brass and plastic material. High-strength, non-destructive water resistant, long service life. Screw terminal type clamps, no need to solder. Waterproof protection, rustproof, can be used in wet or dusty environment. This metal push button switches is easy to install. This momentary switch is on when you press the button, and it is off when you undo the button. Easy disassembly. It can be used as a classic doorbell at home or office, also can be used as a mechanical button. Fit for mounting holes with 16 mm diameter. The metal pressure switch is also used for circuit control in electromagnetic starters, contactors, relays and other circuits. Mounting Hole 16mm Operation Type Momentary .